Re: [libvirt] [PATCH 0/2 v3 use qemu's dump-guest-meory when vm uses host device
At 04/19/2012 04:38 PM, Daniel P. Berrange Wrote: On Thu, Apr 19, 2012 at 09:03:16AM +0800, Wen Congyang wrote: Currently, we use migrate to dump guest's memory. There is one restriction in migrate command: the device's status should be stored in qemu because the device's status should be passed to target machine. If we passthrough a host device to guest, the device's status is stored in the real device. So migrate command will fail. We usually use dump when guest is panicked. So there is no need to store device's status in the vmcore. qemu will have a new monitor command dump-guest-memory to dump guest memory, but it doesn't support async now(it will support later when the common async API is implemented). So I use dump-guest-memory only when the guest uses host device in this patchset. Hmm, doesn't the new command generate dump files in a totally different format to the existing command ? If so I don't think it is nice behaviour to silently switch between 2 different dump formats depending on the XML config. I think we'd want some kind of flag to specify what format is desired. Agree with it. But the new command is not a async command, and it will block the other operation. So I only use it when the vm uses host device(migrate command will fail in this case). The new command will be converted to async command later(after async API is implemented). I think we can allow the user specify the format when the new command is async command. Thanks Wen Congyang Daniel -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
Re: [libvirt] [PATCH 0/2 v3 use qemu's dump-guest-meory when vm uses host device
On Thu, Apr 19, 2012 at 09:03:16AM +0800, Wen Congyang wrote: Currently, we use migrate to dump guest's memory. There is one restriction in migrate command: the device's status should be stored in qemu because the device's status should be passed to target machine. If we passthrough a host device to guest, the device's status is stored in the real device. So migrate command will fail. We usually use dump when guest is panicked. So there is no need to store device's status in the vmcore. qemu will have a new monitor command dump-guest-memory to dump guest memory, but it doesn't support async now(it will support later when the common async API is implemented). So I use dump-guest-memory only when the guest uses host device in this patchset. Hmm, doesn't the new command generate dump files in a totally different format to the existing command ? If so I don't think it is nice behaviour to silently switch between 2 different dump formats depending on the XML config. I think we'd want some kind of flag to specify what format is desired. Daniel -- |: http://berrange.com -o-http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :| -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
Re: [libvirt] [PATCH 0/2 v3 use qemu's dump-guest-meory when vm uses host device
On 04/19/2012 02:45 AM, Wen Congyang wrote: At 04/19/2012 04:38 PM, Daniel P. Berrange Wrote: On Thu, Apr 19, 2012 at 09:03:16AM +0800, Wen Congyang wrote: Currently, we use migrate to dump guest's memory. There is one restriction in migrate command: the device's status should be stored in qemu because the device's status should be passed to target machine. If we passthrough a host device to guest, the device's status is stored in the real device. So migrate command will fail. We usually use dump when guest is panicked. So there is no need to store device's status in the vmcore. qemu will have a new monitor command dump-guest-memory to dump guest memory, but it doesn't support async now(it will support later when the common async API is implemented). So I use dump-guest-memory only when the guest uses host device in this patchset. Hmm, doesn't the new command generate dump files in a totally different format to the existing command ? If so I don't think it is nice behaviour to silently switch between 2 different dump formats depending on the XML config. I think we'd want some kind of flag to specify what format is desired. Agree with it. But the new command is not a async command, and it will block the other operation. So I only use it when the vm uses host device(migrate command will fail in this case). The new command will be converted to async command later(after async API is implemented). I think we can allow the user specify the format when the new command is async command. You missed the point. We need 2 flags - one now that says whether to dump via migrate-to-file or via dumping memory (I'd name it VIR_DOMAIN_CORE_DUMP_MEMORY_ONLY), and another flag later to state whether to block the dump or whether to do the dump asynchronously (similar to the recent block-job-cancel conversion, I'd name it VIR_DOMAIN_CORE_DUMP_ASYNC). In other words, the user should be able to choose which format they get, for 3 of the 4 combinations of user's XML vs. available qemu commands: hostdev no hostdev flag = 0 error migrate-to-file flag = MEMORY_ONLYdump-guest-memory dump-guest-memory and the choice of async or blocking is orthogonal to the above choice. -- Eric Blake ebl...@redhat.com+1-919-301-3266 Libvirt virtualization library http://libvirt.org signature.asc Description: OpenPGP digital signature -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
[libvirt] [PATCH 0/2 v3 use qemu's dump-guest-meory when vm uses host device
Currently, we use migrate to dump guest's memory. There is one restriction in migrate command: the device's status should be stored in qemu because the device's status should be passed to target machine. If we passthrough a host device to guest, the device's status is stored in the real device. So migrate command will fail. We usually use dump when guest is panicked. So there is no need to store device's status in the vmcore. qemu will have a new monitor command dump-guest-memory to dump guest memory, but it doesn't support async now(it will support later when the common async API is implemented). So I use dump-guest-memory only when the guest uses host device in this patchset. Note: the patchset for qemu is still queued. Luiz has acked, but he waits an ACK from Jan and/or Anthony. They are too busy, and donot reply. Changes from v2 to v3: 1. qemu supports the fd that is associated with a pipe, socket, or FIFO. So pass a pipe fd to qemu and O_DIRECT can work now. Change from v1 to v2: 1. remove the implemention for text mode. Wen Congyang (2): qemu: implement qemu's dump-guest-memory qemu: try to use qemu's dump-guest-meory when vm uses host device src/qemu/qemu_domain.c |1 + src/qemu/qemu_domain.h |1 + src/qemu/qemu_driver.c | 39 +-- src/qemu/qemu_monitor.c | 36 src/qemu/qemu_monitor.h | 13 + src/qemu/qemu_monitor_json.c | 42 ++ src/qemu/qemu_monitor_json.h |7 +++ 7 files changed, 137 insertions(+), 2 deletions(-) -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
